Overexpression of the neuron-specific molecule BM88 in mouse neuroblastoma cells: altered responsiveness to growth factors.
Previous studies have shown that the BM88 antigen, a novel neuron-specific molecule, promotes the differentiation of mouse neuroblastoma (Neuro 2a) cells. In particular, stably transfected, with the BM88 cDNA, Neuro 2a cells overexpressing the BM88 antigen (Neuro2a-BM88 cells) are morphologically distinct from the nontransfected Neuro 2a cells; they exhibit enhanced process outgrowth and a slower rate of division. In this study we used Neuro2a and the morphologically differentiated Neuro 2a-BM88 cells to compare their responsiveness to growth factors. The growth factors we used were nerve growth factor (NGF), basic-fibroblast growth factor (b-FGF), and glial cell-line derived neurotrophic factor (GDNF). In addition, we used glial conditioned medium derived from either newborn mouse cerebral cortex (NBCC) or aged mouse cerebral hemispheres (MACH), as a source of normal glial factors. Because these cells express the cholinergic phenotype, we used choline acetyltransferase (ChAT) activity as a biochemical marker for comparison. A differential responsiveness to these factors was observed between Neuro 2a and Neuro 2a-BM88. The presence of NGF, 25 ng/ml, in the culture medium did not affect ChAT activity in either cell type. In contrast to NGF, in the presence of b-FGF, 5 ng/ml, the transfected cells, Neuro 2a-BM88, responded with a marked increase in ChAT activity. On the other hand, with GDNF, 1 ng/ml, only Neuro 2a cells showed an increase in ChAT activity. Finally, we found no response to the glial conditioned media, although these media contain several growth factors, including b-FGF. In conclusion, our findings show that overexpression of the neuron-specific antigen BM88 in neuroblastoma cells modifies their properties with respect to growth factor sensitivity, and, hence, the Neuro 2a and Neuro 2a-BM88 are suitable cell models to examine the role of growth factors in neuronal differentiation.
Gomez
J
J
Department of Psychiatry, University of Colorado Health Science Center, Denver, USA.
Boutou
E
E
Hurel
C
C
Mamalaki
A
A
Kentroti
S
S
Vernadakis
A
A
Matsas
R
R
D000818:Animals; D000951:Antigens, Neoplasm / Q000096:biosynthesis*; D002454:Cell Differentiation / Q000187:drug effects; D017077:Culture Media, Conditioned; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D051100:Glial Cell Line-Derived Neurotrophic Factor; D006133:Growth Substances / Q000494:pharmacology*; D051379:Mice; D009414:Nerve Growth Factors / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000494:pharmacology; D009447:Neuroblastoma / Q000276:immunology; D009474:Neurons / Q000187:drug effects* / Q000276:immunology; D014407:Tumor Cells, Cultured
D000951:Antigens, Neoplasm; D017077:Culture Media, Conditioned; C495040:Gdnf protein, mouse; D051100:Glial Cell Line-Derived Neurotrophic Factor; D006133:Growth Substances; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D016222:Fibroblast Growth Factor 2